Liquid desiccants such as diethylene glycol or triethylene glycol, which may be subsequently referred to simply as glycol, have been widely accepted and are presently being used for dehydrating natural gas streams. The dehydration occurs by the intimate mixing of the gas stream with the liquid desiccant and the removal of water from the gas stream because of the greater affinity of water for the glycol than the gas stream.
The resultant moisture laden or water-rich glycol then must be dehydrated itself. Presently this dehydration of the glycol is accomplished by heating or reboiling the liquid above its boiling point so that the water is driven off and water-lean glycol is collected to be recycled to the contact zone of the natural gas stream.
A fire tube having an open flame is usually utilized to heat the water-laden glycol. In many situations the use of an open flame presents a problem due to the fire danger inherent to the use thereof. One situation occurs on off-shore platforms which are many miles from any fire fighting equipment and hence requires that all fire hazards be reduced to a minimum.
Space on off-shore platforms comes at a premium. Therefore, the normally used reboiler systems which are in the form of vertically stacked elongated horizontal drums very often take up too much floor space.
Most gas gathering systems, have included therein internal combustion type prime movers such as piston driven engines or gas fired turbines which utilize hydrocarbon fluids as fuel. All of these engines produce fairly high temperature exhaust gases, usually in the range from 700.degree. to 1300.degree. F. which when exhausted directly to atmosphere represent the loss of amount of recoverable energy in the form of heat. Such losses have heretofore been considered to be largely unavoidable and in only isolated instances have efforts been extended to recover this energy.
It is therefore an object of this invention to present a method and apparatus for flamelessly reconcentrating liquid desiccant through utilization of heat energy produced by an exhaust gas stream emanating from a prime mover and to perform these functions in a vertically disposed unit having reduced floor space.